The present invention pertains to thermal insulation methods and assemblies for industrial building ceilings. In most commercial settings where steel roofs are found, built-up-roofing (hereinafter "B.U.R.") insulation methods are employed. B.U.R. involves the attachment of rigid insulation on top (i.e., outside) of the roof by affixing a lamination of rigid insulation board, tar paper, gravel and the like. The B.U.R. process, however, is costly and produces only moderate quality thermal insulation. Furthermore, the B.U.R. process can only be applied to metal deck type roofs; it is useless on the low cost standing seam roof which is popular with present day architects.
The author knows of no commercialy acceptable insulation method which can be applied below, rather than above, the roof. Because of the difficulty inherent in working among the bar joists or purlins which support the roof and the attached conduit and fixtures, the only acceptable exposed surface currently available is spray applied fiberglass. Spray fiberglass provides a tight thermal barrier, optical reflection and a neat ceiling appearance around the intricate arrangement of metal bars, pipes and machines attached to the bar joists or purlins for support; however, spray fiberglass applied in more than a thin coating is cost prohibitive, structurally unsound, and overall has little insulating value.
Thus, a need exists for a low cost thermal insulation system/structure which may be used inside--beneath the roof--which provides good thermal insulating properties, pleasing aspect, optical reflection (for maximum ambient light efficiency) and water permeability (to prevent roof rust). The present invention is directed to this specific need.